<div dir="ltr">I agree with uclaros, probably a processing model is what you are looking for, if it fits your processing speed and complexity.... you can also always convert your model in a python script and eventually add some high level parallelization. BTW i.fft would be enough efficient and raster are just linked in grass (automagically by grass provider in processing) without need to import/export.<div><br></div><div>Bye form an ex Barrio de Sampedro citizen</div><div><br></div><div>cheers<br><div><br><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div>Luigi Pirelli<br><br>**************************************************************************************************<br>* LinkedIn: <a href="https://www.linkedin.com/in/luigipirelli" target="_blank">https://www.linkedin.com/in/luigipirelli</a><br>* Stackexchange: <a href="http://gis.stackexchange.com/users/19667/luigi-pirelli" target="_blank">http://gis.stackexchange.com/users/19667/luigi-pirelli</a><br>* GitHub: <a href="https://github.com/luipir" target="_blank">https://github.com/luipir</a><br>* Book: <a href="https://www.packtpub.com/eu/application-development/mastering-geospatial-development-qgis-3x-third-edition" target="_blank">Mastering QGIS3 - 3rd Edition</a></div><div>* Hire a team: <a href="http://www.qcooperative.net" target="_blank">http://www.qcooperative.net</a><br>**************************************************************************************************</div></div></div></div></div></div></div></div></div></div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, 5 Feb 2021 at 17:58, salvador bara <<a href="mailto:salva.bara@gmail.com">salva.bara@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><br clear="all">
<br><div><div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
I'm new to the list, and I apologize in advance if this is not the
proper place for this post. In that case any pointer about where to send
this request would be highly appreciated.<br></div><div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)"><br></div><div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
I am working at Universidade de Santiago de Compostela, in mathematical
methods for light pollution research. Some people asked us for an easy
way to create light pollution maps using QGIS. These maps can be easily
produced by 2-D FFT convolution of georeferenced nighttime satellite
image rasters, using kernels of ~1Mpixel size defined by arbitrary
functions (that is, not just Gaussian ; ) ). We routinely do so using
Matlab, and we have checked that it can also be done using the QGIS menu
after a rather lengthy set of inividual operations based on the i.fft
and i.ifft grass routines. We are assessing the feasibility of writing a
dedicated tutorial on that. However, for most users of QGIS in our
field, this step-by-step algorithm turns out to be a rather cumbersome
procedure.</div><div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)"><br></div><div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
I have to confess I have no programming skills (at all) for
implementing an FFT conv pluging in QGIS. If anyone in the developer
world would be interested in this issue and its potential applications, I
would be happy of cooperating. I am sure there is a large user
community that would take advantage of this feature. For more info about
the underlying methods you may want to have a look to <a href="https://arxiv.org/abs/1907.02891" target="_blank">https://arxiv.org/abs/1907.02891</a><br></div><div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)"> </div><div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)"> All the best,</div><div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)"> salva bará</div></div>
<br>-- <br><div dir="ltr">Salva Bará<br><br>Barrio de San Pedro, Compostela, GALIZA (European Union)<br><br>Esta mensaxe foi enviada utilizando electróns e fotóns 100% reciclados<br>This message has been sent using 100% recycled electrons and photons<br><br></div></div>
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